a(n) = ((n-th prime)^5-(n-th prime)^3)/8.

Terms

a(0) =3a(1) =27a(2) =375a(3) =2058a(4) =19965a(5) =46137a(6) =176868a(7) =308655a(8) =803022a(9) =2560845a(10) =3574920a(11) =8661663a(12) =14473410a(13) =18366117a(14) =28655148a(15) =52255827a(16) =89339865a(17) =105546165a(18) =168728043a(19) =225483930a(20) =259085322a(21) =384570420a(22) =492308607a(23) =697919310a(24) =1073303448